1 files changed, 65 insertions, 0 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ffeebda8d6de..0cb1e1669532 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2761,6 +2761,71 @@ struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start,
 }
 EXPORT_SYMBOL_GPL(iommu_alloc_resv_region);
 
+static int
+request_default_domain_for_dev(struct device *dev, unsigned long type)
+{
+	struct iommu_domain *domain;
+	struct iommu_group *group;
+	int ret;
+
+	/* Device must already be in a group before calling this function */
+	group = iommu_group_get(dev);
+	if (!group)
+		return -EINVAL;
+
+	mutex_lock(&group->mutex);
+
+	ret = 0;
+	if (group->default_domain && group->default_domain->type == type)
+		goto out;
+
+	/* Don't change mappings of existing devices */
+	ret = -EBUSY;
+	if (iommu_group_device_count(group) != 1)
+		goto out;
+
+	ret = -ENOMEM;
+	domain = __iommu_domain_alloc(dev->bus, type);
+	if (!domain)
+		goto out;
+
+	/* Attach the device to the domain */
+	ret = __iommu_attach_group(domain, group);
+	if (ret) {
+		iommu_domain_free(domain);
+		goto out;
+	}
+
+	/* Make the domain the default for this group */
+	if (group->default_domain)
+		iommu_domain_free(group->default_domain);
+	group->default_domain = domain;
+
+	iommu_create_device_direct_mappings(group, dev);
+
+	dev_info(dev, "Using iommu %s mapping\n",
+		 type == IOMMU_DOMAIN_DMA ? "dma" : "direct");
+
+	ret = 0;
+out:
+	mutex_unlock(&group->mutex);
+	iommu_group_put(group);
+
+	return ret;
+}
+
+/* Request that a device is direct mapped by the IOMMU */
+int iommu_request_dm_for_dev(struct device *dev)
+{
+	return request_default_domain_for_dev(dev, IOMMU_DOMAIN_IDENTITY);
+}
+
+/* Request that a device can't be direct mapped by the IOMMU */
+int iommu_request_dma_domain_for_dev(struct device *dev)
+{
+	return request_default_domain_for_dev(dev, IOMMU_DOMAIN_DMA);
+}
+
 void iommu_set_default_passthrough(bool cmd_line)
 {
 	if (cmd_line)